The Aero L-39 Albatros is a high-performance jet trainer aircraft developed in Czechoslovakia to meet requirements for a "C-39" (C for cvičný – trainer) during the 1960s to replace the L-29 Delfín. It was the first of the second-generation jet trainers, and the first turbofan-powered trainer produced, and was later updated as the L-59 Super Albatros and as the L-139 (prototype L-39 with Garrett TFE731 engine).